SIEGEL: Music and fireworks in Moscow today, as Russia formalized its annexation of Crimea. There was a more muted celebration in Brussels, where Ukraine signed a political association agreement with the European Union. Coming up, we'll talk about what Russia's new stance means for the U.S.

CORNISH: But first, to Crimea. Russian forces have occupied Ukrainian military bases one by one as they took over Crimea over the past two weeks. Some Ukrainian soldiers have surrendered peacefully, others are still holding out. NPR's Gregory Warner reports from a base where some Ukrainian soldiers feel abandoned.

GREGORY WARNER, BYLINE: Outside the Ukrainian airbase in Belbek, Crimea, a retired soldier plays soccer with his grandkids. Guys in camouflage chat with women pushing strollers. The first sign that things are not normal here is the huge military vehicle blocking the main gate against an attack by the Russians. Commander Yuli Mamchur says the Russians have given all Ukrainian soldiers in Crimea a deadline of today to evacuate the bases.

WARNER: He also doesn't know what his commanders in Kiev want him to do: Leave Crimea as the Russians demand, or stay and fight, which could mean watching his own men die.

MAMCHUR: (Through Translator) We're not going to shirk our duty. We are military people. Until our government gives us an order, we shall remain here.

WARNER: But here is now de facto foreign territory, not recognized as such by the West but guarded by the superior Russian military. Katya Maslieva is an English professor in the nearby public university in Sevastopol. She says these soldiers are caught between doing their duty and political reality.

KATYA MASLIEVA: They don't want to be Russian, but they don't have opportunity to stay Ukrainian.

WARNER: They're not needed, she says, by Russia, Crimea or Ukraine. And sadly, that's what the soldiers tell me, that when Ukraine split, they lost their place in it. Now, mostly the handover of these bases has been peaceful. So today in Privolnoye, Ukrainian soldiers were filmed exiting the base. Yesterday in Bachyserai, I saw a couple dozen Ukrainian soldiers milling about outside their base, flying a lone Ukrainian flag in the parking lot.

They told me they were waiting for word from Kiev and, not getting it, they drove off in taxis. But rarely has there been a standoff as soldiers planned at this airbase in Belbek. And talking to soldiers here, it seems this potentially suicidal protest is aimed as much at Kiev as Moscow. One soldier, who gave his name as Andrei, tells me he would never desert to join the Russians. But if he slinks back to Kiev without orders, he'll either be jailed as a traitor, he thinks, or at least have no way to provide for his wife and family.

ANDREI: (Through Translator) Just let us come back from Crimea in one piece, for us to be useful to our country in the future. I don't want to die here. But if required, I will die.

WARNER: It's not clear why so many Ukrainian soldiers in Crimea seem to have been abandoned. Whether the fledgling transitional government in Kiev is unable to react to Russia's fast-moving seizure or whether these soldiers, as they fear, have become a political symbol, sacrificed in the altar of Ukraine's outrage. Either way, Andrei says he's heard nothing but silence from his top brass.

ANDREI: (Through Translator) Those who came here with a ruler to check that an outlet was located in the wrong place or that I made a mistake here or there on a document, where are those generals?